Abstract The aim of nuclear safeguards is to ensure that special nuclear material is used for peaceful purposes. Historically, nuclear material accounting NMA has provided the quantitative basis for monitoring for nuclear material loss or diversion, and process monitoring PM data is collected by the operator to monitor the process. PM data typically support NMA in various ways, often by providing a basis to estimate some of the in-process nuclear material inventory. We develop options for combining PM residuals and NMA residuals residual = measurement − prediction, using a hybrid of period-driven and data-driven hypothesis testing. The modified statistical tests can be used on time series of NMA residuals the NMA residual is the familiar material balance, or on a combination of PM and NMA residuals. The PM residuals can be generated on a fixed time schedule or as events occur. View Full-Text